Disclosed herein is an apparatus and method for fuser and pressure assembly temperature control.
Presently, in an image production system, a fuser can be used with a pressure assembly to fuse an image on media. For example, a marking module can mark an image on media with toner, such as ink. A fuser and pressure assembly can then fuse the toner image onto the media by applying heat and pressure to the media at a nip between the fuser and the pressure assembly. A consistent toner-media interface temperature is essential for providing consistent quality prints.
A pressure assembly, such as a pressure roll in a belt fuser architecture, can be covered with a thick overcoat of silicone rubber to provide conformability. Unfortunately, the pressure roll surface temperature varies significantly depending on the media type fed to the pressure roll. Thin media results in higher pressure roll temperatures and thicker cover media results in lower pressure roll temperatures. Too high of a pressure roll temperature can adversely affect duplex quality whereas too low of a pressure roll temperature can adversely affect the image prints. The problem of a unacceptably low pressure roll temperature often occurs when a thin media job immediately follows a long run of thick media or when the pressure roll starts from cold. Furthermore, as many copies are run in a printer, the pressure roll is heated by the fuser in the interdocument zone between copies, which causes its temperature to rise, which adversely affects duplex jobs, results in melting of toner, and destabilizes the toner-paper interface temperature.
If the pressure roll temperature is higher than the set point, an air blower or an air knife is used to cool down the pressure roll by forced convection. Significant air flow is often needed to provide adequate cooling of the pressure roll surface. If the pressure roll temperature is lower than the set point, heat is provided through an internal lamp. Unfortunately, the internal lamp does not consistently and sufficiently control the pressure roll temperature and it is not very efficient because the internal heating has to penetrate through the thick rubber overcoat. Furthermore, the internal heating results in high core temperatures and potential rubber delamination.
Thus, there is a need for apparatus and method that can control fuser and pressure assembly temperature.